Stop collar coupling



Nov. 8, 1960 s. A. WINKELMANN 2,959,435

STOP COLLAR COUPLING Filed Feb. 23, 1954 J4 ii I 200 H IN VEN TOR. 24 a BY M 2 0% STOP COLLAR COUPLING Samuel A. Winkelmann, Houston, Tex., assignor to The guraflex Company, Houston, Tex., a corporation of exas Filed Feb. 23, 1954, Ser. No. 411,652

2 Claims. (Cl. 28752.09)

The present invention relates to a coupling and more particularly relates to a coupling or coupling element which is wedged to a shaft, rod, pipe and the like for a variety of purposes.

While a coupling constructed according to the present invention has an almost unlimited variety of uses in connection with various shafts, pipes, tubes and the like, it is particularly adapted for use in connection with the rotary drilling of oil and gas wells in which various elements, tools and the like, such as scratchers and centralizers, are secured to a string of pipe. Accordingly, the description, for the purpose of disclosure, is directed to that use although other uses and adaptations of the present invention will readily suggest themselves to those skilled in the art.

In preparing oil, gas and like wells for production it is common practice to cement casing in position within the wellbore. This is ordinarily accomplished by circulating cement slurry or cementitious material downwardly through the casing and then upwardly within the well bore and around the casing. The cement is intended to fill the annular space between the casing and the walls of the well bore and to form a suitable bond with the sidewalls of the well.

In the rotary drilling of oil, gas and like wells, drilling mud is circulated downwardly through the string of pipe and out the bit and up the annular space between the string of pipe and the walls of the well bore for a variety of purposes, among which are to lubricate the bit, provide a jetting action on the bottom of the well to aid in drilling, wash the bit cuttings out of the well bore, provide a column of sufficient weight to overcome pressures in formations traversed by the well bore, provide a mud cake on the walls of the well bore to prevent loss of circulation and seal off formations traversed by the well bore, and have thixotropic properties of effectively suspending the cuttings in the well here when the pumping is stopped, but having the ability to commence flowing upon actuation of the pumps again so that the circulating fluid may again be circulated. The circulating drilling fluid or mud has other functions, which are thought unnecessary to mention.

In cementing operations, the presence of a mud cake on the walls of the well bore causes channeling and also prevents the cement from completely filling the annular space between the walls of the well bore and the casing to form a bond between the actual walls of the well bore and the casing. The mud cake left on the wall of the well bore during cementing of a casing, or the like, is often the cause of weakness which may result in failure of the cementing operation and its intended function.

In order to obtain an effective cementing of the casing it is necessary that the bond of the cement with the well bore shall be continuous throughout the area which is desired to be cemented. Also, it is necessary to form a continuous cementing bond behind the casing in any given stratum and a failure of the cement may result in atent O undesirable leakage and in allowing water to invade the producing zone or zones.

In order to assure uniform distribution of cementitious material around the casing and between it and the wall of the well bore, wall scratchers and centralizers have been used which are secured about the exterior of the casing structure.

In general, the wall scratchers condition or abrade the wall of the well bore so that the abraded and loosened mud cake may be flushed out and generally aid in centralizing the casing in the well here thereby providing a satisfactory foundation for the cement. In addition, centralizers are provided so that the casing is positioned substantially equi-distant from the walls of the well bore so that the casing is maintained in centralized position in the well bore as the cement sets thereby providing a continuous column of cementitious material around the casing throughout the cemented area.

In manipulating and lowering these scratchers and centralizers on the casing in the well bore they are subject to forces of considerable magnitude and it is of extreme importance that they be adequately fixed about the casing at spaced intervals and their longitudinal movement with respect to the casing limited or restricted in order that they might perform their intended function upon lowering and manipulating the casing. It is common practice in the industry to prevent axial or longitudinal movement of elements ,such as scratchers and centralizers relative to the casing by means of lugs or projections which are welded to the outer wall of the casing. The welding operation, of course, is a timeconsuming operation and destroys the heat treatment of the pipe at the portions welded. Thus, the welding operation is a time-consuming and expensive operation in which the results are not entirely satisfactory.

It is therefore an object of the present invention to provide a coupling element or stop ring which may easily and quickly be secured about a shaft or structural element, such as a casing, without welding and which is durable and reliable in use and yet inexpensive to manufacture.

It is a further object of the present invention to provide a coupling element or a stop ring of the character mentioned which is securely fixed to the pipe, shaft, structural element, such as a casing, by wedging.

It is yet a further object of the present invention to provide a coupling element or stop ring which has a generally concave inner guide surface which coacts with a generally convex slide surface of a slip wedge so that the element or stop ring rides or slides up on the slip wedge thereby wedging it tighter to the member it engages.

Yet a further object of the present invention is the provision of coupling element or stop ring in which the outer surface is relatively hard and the core is relatively soft of slip segments or wedges utilized, so that the slip segments or wedges frictionally grip the adjacent element with required strength, but yet may be deformed to provide the wedging function.

It is yet a further object of the present invention to provide a stop ringparticularly adapted for use in con,- nection with securing elements and tools, such as scratchers and centralizers, on strings of pipe used in the drilling of oil, gas and like wells, which includes circumferentially-spaced openings through which oppositely extending slip 01 wedge segments are driven to securely wedge the stop ring to the casing.

Other and further objects, advantages and features will be apparent from the following description, given for the purpose of disclosure, and taken in conjunction with the accompanying drawing, where like character references designate like parts throughout the several views, and where Figure 1 is a side elevation illustrating a pair of stop rings according to the invention limiting axial movement of a centralizer relative to casing upon which it is mounted,

' Figure 2 is a cross-sectional view taken along the line 22 of Figure 1 and looking in thedirectionof the I.

i -Figure 3 is a perspective view of a slip or wedge element constructed according to the invention, and' 4 Figure 4 is a side elevation illustrating a stop ring according to the invention limiting axial movement of a scratcher relative to a casing upon which it is mounted. Referring now to the drawing, and particularly to Figure '1, a pair of stop rings constructed according to the invention are illustrated secured about a string of pipe 12, such as a casing, to which is secured the centrali zer1'4. As here illustrated, the pair of stop rings 10 prevent or limit longitudinal or sliding movement of the stabilizer 14 on the casing 12. It should be'noted'that while apair of stop rings 10 are illustrated, only a single stop ring 10 is necessary 'and, in many instances in practice, only a single stop ring 10 is used;

The centralizer 14 may be of any conventional type, for example the centralizer illustrated and described in US. Patent No. 2,628,682, granted February 17, 1953 to K. A. Wright, as well as other types of centralizers utilizedinthe industry. These centralizers are well known and are in wide spread commercial use and, generally, comprise a pair of tubular body members'16 which'are axially spaced and to which are secured the outwardly bowed spring arms 18 to yieldingly centralize the casing 12 in a well bore.

These centralizers may have various types of latching arrangements, not shown, so that they may be secured about the pipe or casing 12 or may merely be slipped over an end of the casing 12. As mentioned previously, it is necessary to provide a means to prevent or restrict longitudinal or sliding movement of the centralizer 14 on the casing 12 when lowering or reciprocating the easing12 in the well bore. Heretofore, the stop means has taken the from of welded lugs, with their inherent disadvantages, as previously mentioned.

Inasmuch as the centralizer as such does not form the present invention, and a variety of such centralizers are in wide spread use in the industry, no more description thereof is deemed necessary.

Referring now to the stop ring 10, which is an example of the present invention, and, as best seen in Figure 2, the stop ring 10 comprises a ring-like body 20 which is in elfeot the stop ring for the centralizer 14, and which fits about the casing 12. While the body 20 fits rather snugly about the pipe 12, a rather small annular space 22 is provided so that the wedge pins or segments 24 may be wedged between the inner surface of the ring member 20 and the outer surface of the casing 12 and the body may be slipped over couplings or tool joints (not shown) by which lengths of the casing 12 are coupled in end-to-end relationship. Preferably, the inner surface of the wedge ring should be concave so that upon axial movement of the ring it will ride or slip up on the outer surface of the slip segments 24 to further wedge these segments against the outer surface of the casing 12, as will be apparent later.

In order that the wedge segments 24 may be driven in between the ring 26 and the casing 12, aspreviously mentioned, a pair of diametrically opposed openings 26 are provided in the ring 20 and, these may be generally oval-shaped, if desired, and as best seen in Figure 1. Obviously, the openings 26 may take a variety of forms, for example, as illustrated in Figure 4, a pair of circumferentially-spaced smaller openings 26a are provided for reception ofthe slip segments 24 which are driven in opposite directions on each side of the stop ring 20.

' The wedge or slip segments 24, as best seen in Figure 3, may have a generally semi-oval surface 28, when viewed in cross-section, and have the teeth 30 on a substantially flat surface to frictionally engage the outer wall of the casing 12. Preferably, the teeth 30 should be arranged in an axial or longitudinal direction to permit the wedge or slip segments 24 to be driven in place, and the teeth 30 are then at an angle of to the direction of force applied to the stop ring 10 in preventing or limiting relative axial movement of the centralizer 14 and the casing 12. Obviously, the teeth 30' may take a variety of forms and, if desired, similar or different teeth to those illustrated at 30 may be provided on the surface 28, which surface may take avariety of shapes, that is, generally flat, rounded, multisided and the like.

Preferably, the slip segments 24 are case-hardened so that their inner surfaces bite into the outer surface of the casing 12, yet the softer inner core permits the slip segments to be deformed between the outer and the inner walls of the casing 12 and body member 20. Also, by providing the outer surface 28 smooth and rounded, the sliding of the concave inner surface of the body member 20 thzreon further wedges the slip segments into the casing 12. The body of the slip segment 24 may be tapered to permit ease of insertion and wedging action thereof in place, as illustrated in Figure 2, and this may take the form of a rounded or tapered end 32, as best seen in Figure 2. Obviously, this tapered portion32 may be relatively short or may be made to extend'and provide a tapered surface substantially the length of the slip segments 24. It is not necessary, however, to provide a tapered surface, in view of the fact that the annular configuration of the space 22 causes a wedging of the slip segments 24 between the outer wall of the casing 12 and the inner wall of the stop ring 10, as is apparent from Figure 2.

The stop ring body 20 and the wedge segments 24 may be formed of many materials, depending upon.the particular use and the strength requirements therefor. Preferably, however, the slip segments should be case-hardened and have a relatively soft inner core. In use in connection with oil well drilling and the like, preferably, the parts should be made of steel and of a size and strength necessary to withstand the forces applied thereto under operating conditions.

In use, for example in securely anchoring or securely limiting axial movement of the centralizer 14 on the casing 12, the centralizer 14 may be secured about the casing 12 by its latching mechanism, not shown, the stop rings 10 having previously been inserted over an end of and disposed about the casing 12. As mentioned previously, the stop ring 10 will be constructed of a size sufiicient to fit over coupling elements, tool joints and the like so that it may be positioned about the casing 12. The slip or wedge segments 24 may be driven or forced into place, as illustrated in Figure 2, by inserting them in generally opposite directions in the openings 26 and driving them into place by means of a hammer or other tool. The stop ring 10 is thereby securely wedged to the casing 12 and it satisfactorily and etfectively prevents dislocation of the centralizer 14, as well as scratchers and the like, along the length of the casing 12, limited sliding of the concave inner guide surface on the outer slide surface 28 of the slip segments 24 further deforming and compressing the latter into frictional engagement with the outer wall of the casing 12.

Thus, an effective and reliable coupling element or stop ring is wedgedly coupled to the casing which reliably and dependably prevents or limits axial movement of the centralizer or scratcher relative to the casing 12 without the necessity of welding the ring 10 to the casing 12 and all its disadvantages. Obviously, the ring may be securely wedged to the casing 12 very rapidly by merely driving or forcing the locking wedge elements or slip segments 24 into place.

It should be noted that the stop rings 10 may be wedgedly secured to the casing 12 before or after the centralizer 14 is positioned about the casing 12 and as mentioned previously, if desired, only a single stop ring may be utilized instead of the pair, as illustrated in Figure 1. While the pair of stop rings 10 may be positioned at the outer ends of the coupling elements 14 and 16, it is preferable to position these interiorly thereof, to permit a flexing action and slight longitudinal movement due to the contraction of the bow springs 18 engaging the walls of the well bore, not shown, when lowering the casing in place or manipulating the casing therein.

Referring now to Figure 4, and as mentioned previously, the stop ring of the present invention may be used to prevent or limit longitudinal or axial movement of the scratcher 3 4 on the pipe or casing 12a. The scratcher 34 as such forms no part of the present invention and any satisfactory or preferred scratcher may be used. Ordinarily, the scratchers utilize a tubular body section 36 which may be latched about the pipe or casing 12a by a latching mechanism, not shown, or slipped over the end thereof, and which has the upwardly and outwardly extending spring fingers 38 which engage the wall of the Well bore, not shown, to scratch and thereby loosen the mud cake thereon so that it might be flushed from the wall of the well bore, as previously described. Any preferred scratcher may be used, such as illustrated in US. Patent No. 2,506,405 granted May 2, 1950 to K. A. Wright; US. Patent No. 2,392,352 granted January 8, 1946 to K. A. Wright; and US. Patent No. 2,634,813 granted April 14, 1953 to K. A. Wright. Other type scratchers, of course, may be used and inasmuch as a variety of scratchers are in wide spread commercial use in the drilling of oil, gas and like wells, no specific description thereof is deemed necessary.

The stop rings 10a illustrated in Figure 4 are in all respects the same as that illustrated in Figures 1 and 2, except that the circumferentially-spaced openings 26a may be provided in and about the ring 20a so that the slip segments 24a may be driven into place, as best seen in Figure 2.

The manner of securing the stop ring 10a to the casing 12a is the same as that described in connection with the centralizer 14; however, in the case of the scratcher, it is preferable to provide a pair of stop rings 10a disposed at the outer surface or edge of the scratcher 34 in order to prevent axial or longitudinal movement thereof with respect to the casing 12a in either direction.

In both cases, the outer shoulder or shoulders of the body 20 or 20a engage or abut against the adjacent member of the centralizer 14 or scratcher 34 to prevent or limit the axial movement as described.

While the present invention is particularly adapted for use in connection with preventing relative longitudinal or axial movement of tools and elements on pipes in the drilling of oil and gas wells and the like, such as the centralizer and scratcher illustrated, the invention may be adapted to couple together various structural elements,

desired to be coupled. These various uses and adaptations will readily suggest themselves to those skilled in the art.

The present invention, therefore, is well suited to carry out the objects and attain the advantages set forth, as wells as others inherent therein. Numerous modifications and rearrangement of parts and details will readily suggest themselves to those skilled in the art which are encompassed within the spirit of the invention and the scope of the appended claims.

What is claimed is:

1. A coupling for engaging and restricting axial movement of tools disposed about pipe comprising, a section of pipe, a ring-like body member having an internal diameter greater than the outer diameter of the section of pipe and suflicient to slip over a coupling connecting lengths of said pipe together, the inner surface of said body member defining a wedge surface, said body member being provided with circumferentially spaced openings, surface-hardened deformable slip inserts insertable in said openings and wedged between said wedge surface and the outer surface of said pipe section thereby wedging the body member to the pipe section, and at least one annular shoulder on said body adapted to engage said tools for limiting or restricting axial movement of the tools on the pipe.

2. A coupling for restricting a tool disposed about pipe from axial movement relative to the pipe comprising, a section of pipe, a ring-like body member having a generally concave inner guide surface disposed about the section of pipe, said guide surface being spaced from the outer surface of said pipe section, said body member being provided with circumferentially spaced openings,

elongate slip segments insertable in said openings and wedged between said guide surface and the outer surface of said pipe section, said slip segments having longitudinally extending surface-hardened teeth for gripping the outer surface of the pipe section in a direction substantially at right angles to the axis of the pipe section, and a generally rounded outer slide surface on said slip segments engaging the guide surface of the body member whereby the slip segments are wedged against the pipe on relative movement of the body member and the pipe section.

References Cited in the file of this patent UNITED STATES PATENTS 331,522 Meese Dec. 1, 1885 2,013,660 Lauer Sept. 10, 1935 2,597,482 Harrison et al May 20, 1952 2,641,810 Gasink June 16, 1953 2,836,447 Wright May 27, 1958 

